Revert 87790 - Removing defunct OpenMAX code.

All of this code hasn't been used in over a year and has been replaced by VideoDecodeAccelerator and it's corresponding OpenMAX implementation OmxVideoDecodeAccelerator.

BUG=none
TEST=the world still compiles

Review URL: http://codereview.chromium.org/7066071

TBR=scherkus@chromium.org
Review URL: http://codereview.chromium.org/7065060

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@87793 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 1603 insertions, 0 deletions

diff --git a/media/video/omx_video_decode_engine.cc b/media/video/omx_video_decode_engine.cc
new file mode 100644
index 0000000..d799ecd
--- /dev/null
+++ b/media/video/omx_video_decode_engine.cc
@@ -0,0 +1,1357 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// This class interacts with OmxCodec and the VideoDecoderImpl
+// in the media pipeline.
+//
+// THREADING SEMANTICS
+//
+// This class is created by OmxVideoDecoder and lives on the thread
+// that it lives. This class is given the message loop
+// for the above thread. The OMX callbacks are guaranteed to be
+// executed on the hosting message loop. Because of that there's no need
+// for locking anywhere.
+
+#include "media/video/omx_video_decode_engine.h"
+
+#include "base/logging.h"
+#include "base/message_loop.h"
+#include "base/string_util.h"
+#include "media/base/buffers.h"
+#include "media/base/pipeline.h"
+
+namespace media {
+
+OmxVideoDecodeEngine::OmxVideoDecodeEngine()
+    : width_(16),
+      height_(16),
+      message_loop_(NULL),
+      input_buffer_count_(0),
+      input_buffer_size_(0),
+      input_port_(0),
+      input_buffers_at_component_(0),
+      input_pending_request_(0),
+      input_queue_has_eos_(false),
+      input_has_fed_eos_(false),
+      input_port_flushed_(false),
+      output_buffer_count_(0),
+      output_buffer_size_(0),
+      output_port_(0),
+      output_buffers_at_component_(0),
+      output_pending_request_(0),
+      output_eos_(false),
+      output_port_flushed_(false),
+      il_state_(kIlNone),
+      expected_il_state_(kIlNone),
+      client_state_(kClientNotInitialized),
+      component_handle_(NULL),
+      need_free_input_buffers_(false),
+      need_free_output_buffers_(false),
+      flush_pending_(false),
+      output_frames_allocated_(false),
+      need_setup_output_port_(false) {
+  // TODO(wjia): change uses_egl_image_ to runtime setup
+#if ENABLE_EGLIMAGE == 1
+  uses_egl_image_ = true;
+  DLOG(INFO) << "Uses egl image for output";
+#else
+  uses_egl_image_ = false;
+  DLOG(INFO) << "Uses system memory for output";
+#endif
+}
+
+OmxVideoDecodeEngine::~OmxVideoDecodeEngine() {
+  DCHECK(client_state_ == kClientNotInitialized ||
+         client_state_ == kClientStopped);
+  DCHECK_EQ(il_state_, kIlNone);
+  DCHECK_EQ(0u, input_buffers_.size());
+  DCHECK(free_input_buffers_.empty());
+  DCHECK(available_input_buffers_.empty());
+  DCHECK_EQ(0, input_buffers_at_component_);
+  DCHECK_EQ(0, output_buffers_at_component_);
+  DCHECK(output_frames_.empty());
+}
+
+template <typename T>
+static void ResetParamHeader(const OmxVideoDecodeEngine& dec, T* param) {
+  memset(param, 0, sizeof(T));
+  param->nVersion.nVersion = dec.current_omx_spec_version();
+  param->nSize = sizeof(T);
+}
+
+void OmxVideoDecodeEngine::Initialize(
+    MessageLoop* message_loop,
+    VideoDecodeEngine::EventHandler* event_handler,
+    VideoDecodeContext* context,
+    const VideoDecoderConfig& config) {
+  DCHECK_EQ(message_loop, MessageLoop::current());
+
+  message_loop_ = message_loop;
+  event_handler_ = event_handler;
+
+  width_ = config.width();
+  height_ = config.height();
+
+  // TODO(wjia): Find the right way to determine the codec type.
+  OmxConfigurator::MediaFormat input_format, output_format;
+  memset(&input_format, 0, sizeof(input_format));
+  memset(&output_format, 0, sizeof(output_format));
+  input_format.codec = OmxConfigurator::kCodecH264;
+  output_format.codec = OmxConfigurator::kCodecRaw;
+  configurator_.reset(
+      new OmxDecoderConfigurator(input_format, output_format));
+
+  // TODO(jiesun): We already ensure Initialize() is called in thread context,
+  // We should try to merge the following function into this function.
+  client_state_ = kClientInitializing;
+  InitializeTask();
+
+  VideoCodecInfo info;
+  // TODO(jiesun): ridiculous, we never fail initialization?
+  info.success = true;
+  info.provides_buffers = !uses_egl_image_;
+  info.stream_info.surface_type =
+      uses_egl_image_ ? VideoFrame::TYPE_GL_TEXTURE
+                      : VideoFrame::TYPE_SYSTEM_MEMORY;
+  info.stream_info.surface_format = GetSurfaceFormat();
+  info.stream_info.surface_width = config.width();
+  info.stream_info.surface_height = config.height();
+  event_handler_->OnInitializeComplete(info);
+}
+
+// This method handles only input buffer, without coupling with output
+void OmxVideoDecodeEngine::ConsumeVideoSample(scoped_refptr<Buffer> buffer) {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+  DCHECK(!free_input_buffers_.empty());
+  DCHECK_GT(input_pending_request_, 0);
+
+  --input_pending_request_;
+
+  if (!CanAcceptInput()) {
+    FinishEmptyBuffer(buffer);
+    return;
+  }
+
+  if (buffer->IsEndOfStream()) {
+    DLOG(INFO) << "Input queue has EOS";
+    input_queue_has_eos_ = true;
+  }
+
+  OMX_BUFFERHEADERTYPE* omx_buffer = free_input_buffers_.front();
+  free_input_buffers_.pop();
+
+  // setup |omx_buffer|.
+  omx_buffer->pBuffer = const_cast<OMX_U8*>(buffer->GetData());
+  omx_buffer->nFilledLen = buffer->GetDataSize();
+  omx_buffer->nAllocLen = omx_buffer->nFilledLen;
+  if (input_queue_has_eos_)
+    omx_buffer->nFlags |= OMX_BUFFERFLAG_EOS;
+  else
+    omx_buffer->nFlags &= ~OMX_BUFFERFLAG_EOS;
+  omx_buffer->nTimeStamp = buffer->GetTimestamp().InMicroseconds();
+  omx_buffer->pAppPrivate = buffer.get();
+  buffer->AddRef();
+  available_input_buffers_.push(omx_buffer);
+
+  // Try to feed buffers into the decoder.
+  EmptyBufferTask();
+
+  if (flush_pending_ && input_pending_request_ == 0)
+    StartFlush();
+}
+
+void OmxVideoDecodeEngine::Flush() {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+  DCHECK_EQ(il_state_, kIlExecuting);
+
+  if (il_state_ != kIlExecuting) {
+    event_handler_->OnFlushComplete();
+    return;
+  }
+
+  client_state_ = kClientFlushing;
+  expected_il_state_ = kIlPause;
+  OnStateSetEventFunc = &OmxVideoDecodeEngine::PauseFromExecuting;
+  TransitionToState(OMX_StatePause);
+}
+
+void OmxVideoDecodeEngine::PauseFromExecuting(OMX_STATETYPE state) {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+
+  OnStateSetEventFunc = NULL;
+  il_state_ = kIlPause;
+
+  if (input_pending_request_ == 0)
+    StartFlush();
+  else
+    flush_pending_ = true;
+}
+
+void OmxVideoDecodeEngine::StartFlush() {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+  DCHECK_EQ(input_pending_request_, 0);
+  DLOG(INFO) << "StartFlush";
+
+  while (!available_input_buffers_.empty())
+    available_input_buffers_.pop();
+
+  flush_pending_ = false;
+
+  // Flush input port first.
+  OnFlushEventFunc = &OmxVideoDecodeEngine::PortFlushDone;
+  OMX_ERRORTYPE omxresult;
+  omxresult = OMX_SendCommand(component_handle_,
+                              OMX_CommandFlush,
+                              input_port_, 0);
+}
+
+bool OmxVideoDecodeEngine::InputPortFlushed() {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+  DCHECK_EQ(client_state_, kClientFlushing);
+  // Port flushed is defined by OpenMAX component had signal flush done and
+  // We had all buffers returned from demuxer and OpenMAX component.
+  int free_input_size = static_cast<int>(free_input_buffers_.size());
+  return input_port_flushed_ && free_input_size == input_buffer_count_;
+}
+
+bool OmxVideoDecodeEngine::OutputPortFlushed() {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+  DCHECK_EQ(client_state_, kClientFlushing);
+  // Port flushed is defined by OpenMAX component had signal flush done and
+  // We had all buffers returned from renderer and OpenMAX component.
+  return output_port_flushed_ && output_pending_request_ == 0;
+}
+
+void OmxVideoDecodeEngine::ComponentFlushDone() {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+  DLOG(INFO) << "Component had been flushed!";
+
+  if (input_port_flushed_ && output_port_flushed_) {
+    event_handler_->OnFlushComplete();
+    input_port_flushed_ = false;
+    output_port_flushed_ = false;
+  }
+}
+
+void OmxVideoDecodeEngine::PortFlushDone(int port) {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+  DCHECK_NE(port, static_cast<int>(OMX_ALL));
+
+  if (port == input_port_) {
+    DLOG(INFO) << "Input Port had been flushed";
+    DCHECK_EQ(input_buffers_at_component_, 0);
+    input_port_flushed_ = true;
+    // Flush output port next.
+    OMX_ERRORTYPE omxresult;
+    omxresult = OMX_SendCommand(component_handle_,
+                                OMX_CommandFlush,
+                                output_port_, 0);
+    return;
+  }
+
+  if (port == output_port_) {
+    DLOG(INFO) << "Output Port had been flushed";
+    DCHECK_EQ(output_buffers_at_component_, 0);
+
+    output_port_flushed_ = true;
+  }
+
+  if (kClientFlushing == client_state_ &&
+      InputPortFlushed() && OutputPortFlushed())
+    ComponentFlushDone();
+}
+
+void OmxVideoDecodeEngine::Seek() {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+
+  DCHECK(client_state_ == kClientFlushing ||     // After a flush
+         client_state_ == kClientInitializing);  // After an initialize.
+
+  if (client_state_ == kClientFlushing) {
+    InitialReadBuffer();
+    OnStateSetEventFunc = &OmxVideoDecodeEngine::DoneSetStateExecuting;
+    TransitionToState(OMX_StateExecuting);
+  }
+
+  event_handler_->OnSeekComplete();
+}
+
+int OmxVideoDecodeEngine::current_omx_spec_version() const {
+  return 0x00000101;
+}
+
+VideoFrame::Format OmxVideoDecodeEngine::GetSurfaceFormat() const {
+  // TODO(jiesun): Both OmxHeaderType and EGLImage surface type could have
+  // different surface formats.
+  return uses_egl_image_ ? VideoFrame::RGBA : VideoFrame::YV12;
+}
+
+void OmxVideoDecodeEngine::Uninitialize() {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+
+  if (client_state_ == kClientError) {
+    OnStopDone();
+    return;
+  }
+
+  // TODO(wjia): add more state checking
+  if (kClientRunning == client_state_ || kClientFlushing == client_state_) {
+    client_state_ = kClientStopping;
+    DeinitFromExecuting(OMX_StateExecuting);
+  }
+
+  // TODO(wjia): When FillThisBuffer() is added, engine state should be
+  // kStopping here. engine state should be set to kStopped in OnStopDone();
+  // client_state_ = kClientStopping;
+}
+
+void OmxVideoDecodeEngine::FinishEmptyBuffer(scoped_refptr<Buffer> buffer) {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+
+  if (!input_queue_has_eos_) {
+    event_handler_->ProduceVideoSample(buffer);
+    ++input_pending_request_;
+  }
+}
+
+void OmxVideoDecodeEngine::FinishFillBuffer(OMX_BUFFERHEADERTYPE* buffer) {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+  DCHECK(buffer);
+
+  scoped_refptr<VideoFrame> frame;
+  frame = static_cast<VideoFrame*>(buffer->pAppPrivate);
+
+  // We should not flush buffer to renderer during decoder flushing if decoder
+  // provides the buffer allocator.
+  if (kClientFlushing == client_state_ && !uses_egl_image_) return;
+
+  PipelineStatistics statistics;
+  statistics.video_bytes_decoded = buffer->nFilledLen;
+
+  frame->SetTimestamp(base::TimeDelta::FromMicroseconds(buffer->nTimeStamp));
+  frame->SetDuration(frame->GetTimestamp() - last_pts_);
+  last_pts_ = frame->GetTimestamp();
+  event_handler_->ConsumeVideoFrame(frame, statistics);
+  output_pending_request_--;
+}
+
+void OmxVideoDecodeEngine::OnStopDone() {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+
+  event_handler_->OnUninitializeComplete();
+}
+
+// Function sequence for initializing
+void OmxVideoDecodeEngine::InitializeTask() {
+  DCHECK_EQ(il_state_, kIlNone);
+
+  il_state_ = kIlNone;
+  expected_il_state_ = kIlLoaded;
+  output_port_state_ = kPortEnabled;
+  if (!CreateComponent()) {
+    StopOnError();
+    return;
+  }
+  il_state_ = kIlLoaded;
+
+  // TODO(wjia): Disabling output port is to work around racing condition
+  // due to bug in some vendor's driver. But it hits another bug.
+  // So temporarily fall back to enabling output port. Still keep the code
+  // disabling output port here.
+  // No need to respond to this PortDisable event
+  // OnPortDisableEventFunc = NULL;
+  // ChangePort(OMX_CommandPortDisable, output_port_);
+  // if (kClientError == client_state_) {
+  //   StopOnError();
+  //   return;
+  // }
+  // output_port_state_ = kPortDisabled;
+
+  // Transition component to Idle state
+  OnStateSetEventFunc = &OmxVideoDecodeEngine::DoneSetStateIdle;
+  if (!TransitionToState(OMX_StateIdle)) {
+    StopOnError();
+    return;
+  }
+  expected_il_state_ = kIlIdle;
+
+  if (!AllocateInputBuffers()) {
+    LOG(ERROR) << "OMX_AllocateBuffer() Input buffer error";
+    client_state_ = kClientError;
+    StopOnError();
+    return;
+  }
+  if (!AllocateOutputBuffers()) {
+    LOG(ERROR) << "OMX_AllocateBuffer() Output buffer error";
+    client_state_ = kClientError;
+    return;
+  }
+}
+
+// Sequence of actions in this transition:
+//
+// 1. Initialize OMX (To be removed.)
+// 2. Map role name to component name.
+// 3. Get handle of the OMX component
+// 4. Get the port information.
+// 5. Set role for the component.
+// 6. Input/output ports media format configuration.
+// 7. Obtain the information about the input port.
+// 8. Obtain the information about the output port.
+bool OmxVideoDecodeEngine::CreateComponent() {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+
+  static OMX_CALLBACKTYPE callback = {
+    &OmxVideoDecodeEngine::EventHandler,
+    &OmxVideoDecodeEngine::EmptyBufferCallback,
+    &OmxVideoDecodeEngine::FillBufferCallback
+  };
+
+  // 1. Initialize the OpenMAX Core.
+  // TODO(hclam): move this out.
+  OMX_ERRORTYPE omxresult = OMX_Init();
+  if (omxresult != OMX_ErrorNone) {
+    LOG(ERROR) << "Failed to init OpenMAX core";
+    client_state_ = kClientError;
+    return false;
+  }
+
+  // 2. Map role name to component name.
+  std::string role_name = configurator_->GetRoleName();
+  OMX_U32 roles = 0;
+  omxresult = OMX_GetComponentsOfRole(
+      const_cast<OMX_STRING>(role_name.c_str()),
+      &roles, 0);
+  if (omxresult != OMX_ErrorNone || roles == 0) {
+    LOG(ERROR) << "Unsupported Role: " << role_name.c_str();
+    client_state_ = kClientError;
+    return false;
+  }
+  const OMX_U32 kMaxRolePerComponent = 20;
+  CHECK(roles < kMaxRolePerComponent);
+
+  OMX_U8** component_names = new OMX_U8*[roles];
+  const int kMaxComponentNameLength = 256;
+  for (size_t i = 0; i < roles; ++i)
+    component_names[i] = new OMX_U8[kMaxComponentNameLength];
+
+  omxresult = OMX_GetComponentsOfRole(
+      const_cast<OMX_STRING>(role_name.c_str()),
+      &roles, component_names);
+
+  // Use first component only. Copy the name of the first component
+  // so that we could free the memory.
+  std::string component_name;
+  if (omxresult == OMX_ErrorNone)
+    component_name = reinterpret_cast<char*>(component_names[0]);
+
+  for (size_t i = 0; i < roles; ++i)
+    delete [] component_names[i];
+  delete [] component_names;
+
+  if (omxresult != OMX_ErrorNone || roles == 0) {
+    LOG(ERROR) << "Unsupported Role: " << role_name.c_str();
+    client_state_ = kClientError;
+    return false;
+  }
+
+  // 3. Get the handle to the component. After OMX_GetHandle(),
+  //    the component is in loaded state.
+  OMX_STRING component = const_cast<OMX_STRING>(component_name.c_str());
+  omxresult = OMX_GetHandle(&component_handle_, component, this, &callback);
+  if (omxresult != OMX_ErrorNone) {
+    LOG(ERROR) << "Failed to Load the component: " << component;
+    client_state_ = kClientError;
+    return false;
+  }
+
+  // 4. Get the port information. This will obtain information about the
+  //    number of ports and index of the first port.
+  OMX_PORT_PARAM_TYPE port_param;
+  ResetParamHeader(*this, &port_param);
+  omxresult = OMX_GetParameter(component_handle_, OMX_IndexParamVideoInit,
+                               &port_param);
+  if (omxresult != OMX_ErrorNone) {
+    LOG(ERROR) << "Failed to get Port Param";
+    client_state_ = kClientError;
+    return false;
+  }
+  input_port_ = port_param.nStartPortNumber;
+  output_port_ = input_port_ + 1;
+
+  // 5. Set role for the component because our component could
+  //    have multiple roles.
+  OMX_PARAM_COMPONENTROLETYPE role_type;
+  ResetParamHeader(*this, &role_type);
+  base::strlcpy(reinterpret_cast<char*>(role_type.cRole),
+                role_name.c_str(),
+                OMX_MAX_STRINGNAME_SIZE);
+  role_type.cRole[OMX_MAX_STRINGNAME_SIZE - 1] = '\0';
+  omxresult = OMX_SetParameter(component_handle_,
+                               OMX_IndexParamStandardComponentRole,
+                               &role_type);
+  if (omxresult != OMX_ErrorNone) {
+    LOG(ERROR) << "Failed to Set Role";
+    client_state_ = kClientError;
+    return false;
+  }
+
+  // 6. Input/output ports media format configuration.
+  if (!ConfigureIOPorts()) {
+    LOG(ERROR) << "Media format configurations failed";
+    client_state_ = kClientError;
+    return false;
+  }
+
+  // 7. Obtain the information about the input port.
+  // This will have the new mini buffer count in |port_format.nBufferCountMin|.
+  // Save this value to input_buf_count.
+  OMX_PARAM_PORTDEFINITIONTYPE port_format;
+  ResetParamHeader(*this, &port_format);
+  port_format.nPortIndex = input_port_;
+  omxresult = OMX_GetParameter(component_handle_,
+                               OMX_IndexParamPortDefinition,
+                               &port_format);
+  if (omxresult != OMX_ErrorNone) {
+    LOG(ERROR) << "GetParameter(OMX_IndexParamPortDefinition) failed";
+    client_state_ = kClientError;
+    return false;
+  }
+  if (OMX_DirInput != port_format.eDir) {
+    LOG(ERROR) << "Expected input port";
+    client_state_ = kClientError;
+    return false;
+  }
+  input_buffer_count_ = port_format.nBufferCountActual;
+  input_buffer_size_ = port_format.nBufferSize;
+
+  // 8. Obtain the information about the output port.
+  ResetParamHeader(*this, &port_format);
+  port_format.nPortIndex = output_port_;
+  omxresult = OMX_GetParameter(component_handle_,
+                               OMX_IndexParamPortDefinition,
+                               &port_format);
+  if (omxresult != OMX_ErrorNone) {
+    LOG(ERROR) << "GetParameter(OMX_IndexParamPortDefinition) failed";
+    client_state_ = kClientError;
+    return false;
+  }
+  if (OMX_DirOutput != port_format.eDir) {
+    LOG(ERROR) << "Expect Output Port";
+    client_state_ = kClientError;
+    return false;
+  }
+
+  // TODO(wjia): use same buffer recycling for EGLImage and system memory.
+  // Override buffer count when EGLImage is used.
+  if (uses_egl_image_) {
+    // TODO(wjia): remove hard-coded value
+    port_format.nBufferCountActual = port_format.nBufferCountMin =
+       output_buffer_count_ = 4;
+
+    omxresult = OMX_SetParameter(component_handle_,
+                                 OMX_IndexParamPortDefinition,
+                                 &port_format);
+    if (omxresult != OMX_ErrorNone) {
+      LOG(ERROR) << "SetParameter(OMX_IndexParamPortDefinition) failed";
+      client_state_ = kClientError;
+      return false;
+    }
+  } else {
+    output_buffer_count_ = port_format.nBufferCountActual;
+  }
+  output_buffer_size_ = port_format.nBufferSize;
+
+  return true;
+}
+
+// Event callback during initialization to handle DoneStateSet to idle
+void OmxVideoDecodeEngine::DoneSetStateIdle(OMX_STATETYPE state) {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+  DCHECK_EQ(client_state_, kClientInitializing);
+  DCHECK_EQ(OMX_StateIdle, state);
+  DLOG(INFO) << "OMX video decode engine is in Idle";
+
+  il_state_ = kIlIdle;
+
+  // start reading bit stream
+  InitialReadBuffer();
+  OnStateSetEventFunc = &OmxVideoDecodeEngine::DoneSetStateExecuting;
+  if (!TransitionToState(OMX_StateExecuting)) {
+    StopOnError();
+    return;
+  }
+  expected_il_state_ = kIlExecuting;
+}
+
+// Event callback during initialization to handle DoneStateSet to executing
+void OmxVideoDecodeEngine::DoneSetStateExecuting(OMX_STATETYPE state) {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+  DCHECK(client_state_ == kClientInitializing ||
+         client_state_ == kClientFlushing);
+  DCHECK_EQ(OMX_StateExecuting, state);
+  DLOG(INFO) << "OMX video decode engine is in Executing";
+
+  il_state_ = kIlExecuting;
+  client_state_ = kClientRunning;
+  OnStateSetEventFunc = NULL;
+  EmptyBufferTask();
+  InitialFillBuffer();
+  if (kClientError == client_state_) {
+    StopOnError();
+    return;
+  }
+}
+
+// Function for receiving output buffers. Hookup for buffer recycling
+// and outside allocator.
+void OmxVideoDecodeEngine::ProduceVideoFrame(
+    scoped_refptr<VideoFrame> video_frame) {
+  DCHECK(video_frame.get() && !video_frame->IsEndOfStream());
+  output_pending_request_++;
+
+  PipelineStatistics statistics;
+
+  if (!CanAcceptOutput()) {
+    if (uses_egl_image_) {  // return it to owner.
+      output_pending_request_--;
+      event_handler_->ConsumeVideoFrame(video_frame, statistics);
+    }
+    return;
+  }
+
+  OMX_BUFFERHEADERTYPE* omx_buffer = FindOmxBuffer(video_frame);
+  if (omx_buffer) {
+    statistics.video_bytes_decoded = omx_buffer->nFilledLen;
+
+    if (kClientRunning == client_state_) {
+      SendOutputBufferToComponent(omx_buffer);
+    } else if (kClientFlushing == client_state_) {
+      if (uses_egl_image_) {  // return it to owner.
+        output_pending_request_--;
+        event_handler_->ConsumeVideoFrame(video_frame, statistics);
+      }
+      if (InputPortFlushed() && OutputPortFlushed())
+        ComponentFlushDone();
+    }
+  } else {
+    DCHECK(!output_frames_allocated_);
+    DCHECK(uses_egl_image_);
+    output_frames_.push_back(std::make_pair(video_frame,
+        static_cast<OMX_BUFFERHEADERTYPE*>(NULL)));
+  }
+
+  DCHECK(static_cast<int>(output_frames_.size()) <= output_buffer_count_);
+
+  if ((!output_frames_allocated_) &&
+      static_cast<int>(output_frames_.size()) == output_buffer_count_) {
+    output_frames_allocated_ = true;
+
+    if (need_setup_output_port_) {
+      SetupOutputPort();
+    }
+  }
+
+  if (kClientError == client_state_) {
+    StopOnError();
+    return;
+  }
+}
+
+// Reconfigure port
+void OmxVideoDecodeEngine::OnPortSettingsChangedRun(int port,
+                                                    OMX_INDEXTYPE index) {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+  DCHECK_EQ(client_state_, kClientRunning);
+  DCHECK_EQ(port, output_port_);
+
+  // TODO(wjia): add buffer negotiation between decoder and renderer.
+  if (uses_egl_image_) {
+    DLOG(INFO) << "Port settings are changed";
+    return;
+  }
+
+  // TODO(wjia): remove this checking when all vendors observe same spec.
+  if (index > OMX_IndexComponentStartUnused) {
+    if (index != OMX_IndexParamPortDefinition)
+      return;
+  }
+
+  OMX_PARAM_PORTDEFINITIONTYPE port_format;
+  ResetParamHeader(*this, &port_format);
+  port_format.nPortIndex = output_port_;
+  OMX_ERRORTYPE omxresult;
+  omxresult = OMX_GetParameter(component_handle_,
+                               OMX_IndexParamPortDefinition,
+                               &port_format);
+  if (omxresult != OMX_ErrorNone) {
+    LOG(ERROR) << "GetParameter(OMX_IndexParamPortDefinition) failed";
+    client_state_ = kClientError;
+    StopOnError();
+    return;
+  }
+  if (OMX_DirOutput != port_format.eDir) {
+    LOG(ERROR) << "Expected Output Port";
+    client_state_ = kClientError;
+    StopOnError();
+    return;
+  }
+
+  // Update the output format.
+  OmxConfigurator::MediaFormat output_format;
+  output_format.video_header.height = port_format.format.video.nFrameHeight;
+  output_format.video_header.width = port_format.format.video.nFrameWidth;
+  output_format.video_header.stride = port_format.format.video.nStride;
+  output_buffer_count_ = port_format.nBufferCountActual;
+  output_buffer_size_ = port_format.nBufferSize;
+
+  if (kPortEnabled == output_port_state_) {
+    output_port_state_ = kPortDisabling;
+    OnPortDisableEventFunc = &OmxVideoDecodeEngine::OnPortDisableEventRun;
+    ChangePort(OMX_CommandPortDisable, output_port_);
+    if (kClientError == client_state_) {
+      StopOnError();
+      return;
+    }
+    FreeOutputBuffers();
+  } else {
+    OnPortDisableEventRun(output_port_);
+  }
+}
+
+// Post output port disabling
+void OmxVideoDecodeEngine::OnPortDisableEventRun(int port) {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+  DCHECK_EQ(client_state_, kClientRunning);
+  DCHECK_EQ(port, output_port_);
+
+  output_port_state_ = kPortDisabled;
+
+  // make sure all eglimages are available before enabling output port
+  if (output_frames_allocated_ || !uses_egl_image_) {
+    SetupOutputPort();
+    if (kClientError == client_state_) {
+      StopOnError();
+      return;
+    }
+  } else {
+    need_setup_output_port_ = true;
+  }
+}
+
+// Enable output port and allocate buffers correspondingly
+void OmxVideoDecodeEngine::SetupOutputPort() {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+
+  need_setup_output_port_ = false;
+
+  // Enable output port when necessary since the port could be waiting for
+  // buffers, instead of port reconfiguration.
+  if (kPortEnabled != output_port_state_) {
+    output_port_state_ = kPortEnabling;
+    OnPortEnableEventFunc = &OmxVideoDecodeEngine::OnPortEnableEventRun;
+    ChangePort(OMX_CommandPortEnable, output_port_);
+    if (kClientError == client_state_) {
+      return;
+    }
+  }
+
+  // TODO(wjia): add state checking
+  // Update the ports in buffer if necessary
+  if (!AllocateOutputBuffers()) {
+    LOG(ERROR) << "OMX_AllocateBuffer() Output buffer error";
+    client_state_ = kClientError;
+    return;
+  }
+}
+
+// Post output port enabling
+void OmxVideoDecodeEngine::OnPortEnableEventRun(int port) {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+  DCHECK_EQ(port, output_port_);
+  DCHECK_EQ(client_state_, kClientRunning);
+
+  output_port_state_ = kPortEnabled;
+  last_pts_ = base::TimeDelta::FromMilliseconds(0);
+  OnPortEnableEventFunc = NULL;
+  InitialFillBuffer();
+  if (kClientError == client_state_) {
+    StopOnError();
+    return;
+  }
+}
+
+void OmxVideoDecodeEngine::DeinitFromExecuting(OMX_STATETYPE state) {
+  DCHECK_EQ(state, OMX_StateExecuting);
+
+  DLOG(INFO) << "Deinit from Executing";
+  OnStateSetEventFunc = &OmxVideoDecodeEngine::DeinitFromIdle;
+  TransitionToState(OMX_StateIdle);
+  expected_il_state_ = kIlIdle;
+}
+
+void OmxVideoDecodeEngine::DeinitFromIdle(OMX_STATETYPE state) {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+  DCHECK_EQ(state, OMX_StateIdle);
+
+  DLOG(INFO) << "Deinit from Idle";
+  il_state_ = kIlIdle;
+  OnStateSetEventFunc = &OmxVideoDecodeEngine::DeinitFromLoaded;
+  TransitionToState(OMX_StateLoaded);
+  expected_il_state_ = kIlLoaded;
+
+  if (!input_buffers_at_component_)
+    FreeInputBuffers();
+  else
+    need_free_input_buffers_ = true;
+
+  if (!output_buffers_at_component_)
+    FreeOutputBuffers();
+  else
+    need_free_output_buffers_ = true;
+}
+
+void OmxVideoDecodeEngine::DeinitFromLoaded(OMX_STATETYPE state) {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+  DCHECK_EQ(state, OMX_StateLoaded);
+
+  DLOG(INFO) << "Deinit from Loaded";
+  il_state_ = kIlLoaded;
+  if (component_handle_) {
+    OMX_ERRORTYPE result = OMX_FreeHandle(component_handle_);
+    if (result != OMX_ErrorNone)
+      LOG(ERROR) << "OMX_FreeHandle() error. Error code: " << result;
+    component_handle_ = NULL;
+  }
+  il_state_ = expected_il_state_ = kIlNone;
+
+  // kClientStopped is different from kClientNotInitialized. The former can't
+  // accept output buffers, while the latter can.
+  client_state_ = kClientStopped;
+
+  OMX_Deinit();
+
+  OnStopDone();
+}
+
+void OmxVideoDecodeEngine::StopOnError() {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+
+  client_state_ = kClientStopping;
+
+  if (kIlExecuting == expected_il_state_) {
+    DeinitFromExecuting(OMX_StateExecuting);
+  } else if (kIlIdle == expected_il_state_) {
+    DeinitFromIdle(OMX_StateIdle);
+  } else if (kIlLoaded == expected_il_state_) {
+    DeinitFromLoaded(OMX_StateLoaded);
+  } else if (kIlPause == expected_il_state_) {
+    // TODO(jiesun): Make sure this works.
+    DeinitFromExecuting(OMX_StateExecuting);
+  } else {
+    NOTREACHED();
+  }
+}
+
+// Call OMX_UseBuffer() to avoid buffer copying when
+// OMX_EmptyThisBuffer() is called
+bool OmxVideoDecodeEngine::AllocateInputBuffers() {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+
+  uint8* data = new uint8[input_buffer_size_];
+  scoped_array<uint8> data_deleter(data);
+
+  for (int i = 0; i < input_buffer_count_; ++i) {
+    OMX_BUFFERHEADERTYPE* buffer;
+    OMX_ERRORTYPE error =
+        OMX_UseBuffer(component_handle_, &buffer, input_port_,
+                      this, input_buffer_size_, data);
+    if (error != OMX_ErrorNone)
+      return false;
+    buffer->nInputPortIndex = input_port_;
+    buffer->nOffset = 0;
+    buffer->nFlags = 0;
+    input_buffers_.push_back(buffer);
+    free_input_buffers_.push(buffer);
+  }
+  return true;
+}
+
+// This method handles EGLImage and internal buffer cases. Any external
+// allocation case is similar to EGLImage
+bool OmxVideoDecodeEngine::AllocateOutputBuffers() {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+
+  if (uses_egl_image_ && !output_frames_allocated_) {
+    DLOG(INFO) << "Output frames are not allocated yet";
+    need_setup_output_port_ = true;
+    return true;
+  }
+
+  for (int i = 0; i < output_buffer_count_; ++i) {
+    OMX_BUFFERHEADERTYPE* buffer;
+    scoped_refptr<VideoFrame> video_frame;
+    OMX_ERRORTYPE error;
+    if (uses_egl_image_) {
+      OutputFrame output_frame = output_frames_[i];
+      video_frame = output_frame.first;
+      DCHECK(!output_frame.second);
+      error = OMX_UseEGLImage(component_handle_, &buffer, output_port_,
+                              video_frame.get(), video_frame->private_buffer());
+      if (error != OMX_ErrorNone)
+        return false;
+      output_frames_[i].second = buffer;
+    } else {
+      error = OMX_AllocateBuffer(component_handle_, &buffer, output_port_,
+                                 NULL, output_buffer_size_);
+      if (error != OMX_ErrorNone)
+        return false;
+      video_frame = CreateOmxBufferVideoFrame(buffer);
+      output_frames_.push_back(std::make_pair(video_frame, buffer));
+      buffer->pAppPrivate = video_frame.get();
+    }
+  }
+
+  return true;
+}
+
+scoped_refptr<VideoFrame> OmxVideoDecodeEngine::CreateOmxBufferVideoFrame(
+    OMX_BUFFERHEADERTYPE* omx_buffer) {
+  scoped_refptr<VideoFrame> video_frame;
+  uint8* data[VideoFrame::kMaxPlanes];
+  int32 strides[VideoFrame::kMaxPlanes];
+
+  memset(data, 0, sizeof(data));
+  memset(strides, 0, sizeof(strides));
+  // TODO(jiesun): chroma format 4:2:0 only and 3 planes.
+  data[0] = omx_buffer->pBuffer;
+  data[1] = data[0] + width_ * height_;
+  data[2] = data[1] + width_ * height_ / 4;
+  strides[0] = width_;
+  strides[1] = strides[2] = width_ >> 1;
+
+  VideoFrame::CreateFrameExternal(
+      VideoFrame::TYPE_SYSTEM_MEMORY,
+      VideoFrame::YV12,
+      width_, height_, 3,
+      data, strides,
+      kNoTimestamp,
+      kNoTimestamp,
+      omx_buffer,
+      &video_frame);
+
+  return video_frame;
+}
+
+void OmxVideoDecodeEngine::FreeInputBuffers() {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+
+  // Empty available buffer queue.
+  while (!free_input_buffers_.empty()) {
+    free_input_buffers_.pop();
+  }
+
+  while (!available_input_buffers_.empty()) {
+    OMX_BUFFERHEADERTYPE* omx_buffer = available_input_buffers_.front();
+    available_input_buffers_.pop();
+    Buffer* stored_buffer = static_cast<Buffer*>(omx_buffer->pAppPrivate);
+    FinishEmptyBuffer(stored_buffer);
+    stored_buffer->Release();
+  }
+
+  // Calls to OMX to free buffers.
+  for (size_t i = 0; i < input_buffers_.size(); ++i)
+    OMX_FreeBuffer(component_handle_, input_port_, input_buffers_[i]);
+  input_buffers_.clear();
+
+  need_free_input_buffers_ = false;
+}
+
+void OmxVideoDecodeEngine::FreeOutputBuffers() {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+
+  // Calls to OMX to free buffers.
+  for (size_t i = 0; i < output_frames_.size(); ++i) {
+    OMX_BUFFERHEADERTYPE* omx_buffer = output_frames_[i].second;
+    CHECK(omx_buffer);
+    OMX_FreeBuffer(component_handle_, output_port_, omx_buffer);
+  }
+  output_frames_.clear();
+  output_frames_allocated_ = false;
+
+  need_free_output_buffers_ = false;
+}
+
+bool OmxVideoDecodeEngine::ConfigureIOPorts() {
+  OMX_PARAM_PORTDEFINITIONTYPE input_port_def, output_port_def;
+  OMX_ERRORTYPE omxresult = OMX_ErrorNone;
+  // Get default input port definition.
+  ResetParamHeader(*this, &input_port_def);
+  input_port_def.nPortIndex = input_port_;
+  omxresult = OMX_GetParameter(component_handle_,
+                               OMX_IndexParamPortDefinition,
+                               &input_port_def);
+  if (omxresult != OMX_ErrorNone) {
+    LOG(ERROR) << "GetParameter(OMX_IndexParamPortDefinition) "
+               << "for input port failed";
+    return false;
+  }
+  if (OMX_DirInput != input_port_def.eDir) {
+    LOG(ERROR) << "Expected Input Port";
+    return false;
+  }
+
+  // Get default output port definition.
+  ResetParamHeader(*this, &output_port_def);
+  output_port_def.nPortIndex = output_port_;
+  omxresult = OMX_GetParameter(component_handle_,
+                               OMX_IndexParamPortDefinition,
+                               &output_port_def);
+  if (omxresult != OMX_ErrorNone) {
+    LOG(ERROR) << "GetParameter(OMX_IndexParamPortDefinition) "
+               << "for output port failed";
+    return false;
+  }
+  if (OMX_DirOutput != output_port_def.eDir) {
+    LOG(ERROR) << "Expected Output Port";
+    return false;
+  }
+
+  return configurator_->ConfigureIOPorts(
+      static_cast<OMX_COMPONENTTYPE*>(component_handle_),
+      &input_port_def, &output_port_def);
+}
+
+bool OmxVideoDecodeEngine::CanEmptyBuffer() {
+  // We can call empty buffer while we are in executing and EOS has
+  // not been sent
+  return (il_state_ == kIlExecuting &&
+          !input_has_fed_eos_);
+}
+
+bool OmxVideoDecodeEngine::CanFillBuffer() {
+  // Make sure component is in the executing state and end-of-stream
+  // has not been reached.
+  return (il_state_ == kIlExecuting &&
+          !output_eos_ &&
+          (output_port_state_ == kPortEnabled ||
+           output_port_state_ == kPortEnabling));
+}
+
+bool OmxVideoDecodeEngine::CanAcceptInput() {
+  // We can't take input buffer when in error state.
+  return (kClientError != client_state_ &&
+          kClientStopping != client_state_ &&
+          kClientStopped != client_state_ &&
+          !input_queue_has_eos_);
+}
+
+bool OmxVideoDecodeEngine::CanAcceptOutput() {
+  return (kClientError != client_state_ &&
+          kClientStopping != client_state_ &&
+          kClientStopped != client_state_ &&
+          output_port_state_ == kPortEnabled &&
+          !output_eos_);
+}
+
+// TODO(wjia): There are several things need to be done here:
+// 1. Merge this method into EmptyThisBuffer();
+// 2. Get rid of the while loop, this is not needed because when we call
+// OMX_EmptyThisBuffer we assume we *always* have an input buffer.
+void OmxVideoDecodeEngine::EmptyBufferTask() {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+
+  if (!CanEmptyBuffer())
+    return;
+
+  // Loop for all available input data and input buffer for the
+  // decoder. When input has reached EOS  we need to stop.
+  while (!available_input_buffers_.empty() &&
+         !input_has_fed_eos_) {
+    OMX_BUFFERHEADERTYPE* omx_buffer = available_input_buffers_.front();
+    available_input_buffers_.pop();
+
+    input_has_fed_eos_ = omx_buffer->nFlags & OMX_BUFFERFLAG_EOS;
+    if (input_has_fed_eos_) {
+      DLOG(INFO) << "Input has fed EOS";
+    }
+
+    // Give this buffer to OMX.
+    input_buffers_at_component_++;
+    OMX_ERRORTYPE ret = OMX_EmptyThisBuffer(component_handle_, omx_buffer);
+    if (ret != OMX_ErrorNone) {
+      LOG(ERROR) << "OMX_EmptyThisBuffer() failed with result " << ret;
+      client_state_ = kClientError;
+      return;
+    }
+  }
+}
+
+void OmxVideoDecodeEngine::InitialReadBuffer() {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+
+  input_queue_has_eos_ = false;
+  input_has_fed_eos_ = false;
+  output_eos_ = false;
+
+  DLOG(INFO) << "OmxVideoDecodeEngine::InitialReadBuffer";
+  for (size_t i = 0; i < free_input_buffers_.size(); i++)
+    FinishEmptyBuffer(NULL);
+}
+
+void OmxVideoDecodeEngine::InitialFillBuffer() {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+  // DCHECK(output_frames_allocated_);
+
+  if (!CanFillBuffer())
+    return;
+
+  DLOG(INFO) << "OmxVideoDecodeEngine::InitialFillBuffer";
+
+  // Ask the decoder to fill the output buffers.
+  for (uint32 i = 0; i < output_frames_.size(); ++i) {
+    OMX_BUFFERHEADERTYPE* omx_buffer = output_frames_[i].second;
+    SendOutputBufferToComponent(omx_buffer);
+  }
+}
+
+// helper functions
+// Send command to disable/enable port.
+void OmxVideoDecodeEngine::ChangePort(OMX_COMMANDTYPE cmd, int port_index) {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+
+  OMX_ERRORTYPE omxresult = OMX_SendCommand(component_handle_,
+                                            cmd, port_index, 0);
+  if (omxresult != OMX_ErrorNone) {
+    LOG(ERROR) << "SendCommand(OMX_CommandPortDisable) failed";
+    client_state_ = kClientError;
+    return;
+  }
+}
+
+// Find if omx_buffer exists corresponding to video_frame
+OMX_BUFFERHEADERTYPE* OmxVideoDecodeEngine::FindOmxBuffer(
+    scoped_refptr<VideoFrame> video_frame) {
+  for (size_t i = 0; i < output_frames_.size(); ++i) {
+    if (video_frame == output_frames_[i].first)
+      return output_frames_[i].second;
+  }
+  return NULL;
+}
+
+OMX_STATETYPE OmxVideoDecodeEngine::GetComponentState() {
+  OMX_STATETYPE eState;
+  OMX_ERRORTYPE eError;
+
+  eError = OMX_GetState(component_handle_, &eState);
+  if (OMX_ErrorNone != eError) {
+    LOG(ERROR) << "OMX_GetState failed";
+    StopOnError();
+  }
+
+  return eState;
+}
+
+// send one output buffer to component
+void OmxVideoDecodeEngine::SendOutputBufferToComponent(
+    OMX_BUFFERHEADERTYPE *omx_buffer) {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+
+  if (!CanFillBuffer())
+    return;
+
+  // clear EOS flag.
+  omx_buffer->nFlags &= ~OMX_BUFFERFLAG_EOS;
+  omx_buffer->nOutputPortIndex = output_port_;
+  output_buffers_at_component_++;
+  OMX_ERRORTYPE ret = OMX_FillThisBuffer(component_handle_, omx_buffer);
+
+  if (OMX_ErrorNone != ret) {
+    LOG(ERROR) << "OMX_FillThisBuffer() failed with result " << ret;
+    client_state_ = kClientError;
+    return;
+  }
+}
+
+// Send state transition command to component.
+bool OmxVideoDecodeEngine::TransitionToState(OMX_STATETYPE new_state) {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+
+  OMX_ERRORTYPE omxresult = OMX_SendCommand(component_handle_,
+                                            OMX_CommandStateSet,
+                                            new_state, 0);
+  if (omxresult != OMX_ErrorNone) {
+    LOG(ERROR) << "SendCommand(OMX_CommandStateSet) failed";
+    client_state_ = kClientError;
+    return false;
+  }
+
+  return true;
+}
+
+void OmxVideoDecodeEngine::EmptyBufferDoneTask(OMX_BUFFERHEADERTYPE* buffer) {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+  DCHECK_GT(input_buffers_at_component_, 0);
+
+  Buffer* stored_buffer = static_cast<Buffer*>(buffer->pAppPrivate);
+  buffer->pAppPrivate = NULL;
+  if (client_state_ != kClientFlushing)
+    FinishEmptyBuffer(stored_buffer);
+  stored_buffer->Release();
+
+  // Enqueue the available buffer because the decoder has consumed it.
+  free_input_buffers_.push(buffer);
+  input_buffers_at_component_--;
+
+  if (need_free_input_buffers_ && !input_buffers_at_component_) {
+    FreeInputBuffers();
+    return;
+  }
+
+  // Try to feed more data into the decoder.
+  EmptyBufferTask();
+
+  if (client_state_ == kClientFlushing &&
+      InputPortFlushed() && OutputPortFlushed())
+    ComponentFlushDone();
+}
+
+void OmxVideoDecodeEngine::FillBufferDoneTask(OMX_BUFFERHEADERTYPE* buffer) {
+  DCHECK_EQ(message_loop_, MessageLoop::current());
+  DCHECK_GT(output_buffers_at_component_, 0);
+
+  output_buffers_at_component_--;
+
+  if (need_free_output_buffers_ && !output_buffers_at_component_) {
+    FreeOutputBuffers();
+    return;
+  }
+
+  PipelineStatistics statistics;
+  statistics.video_bytes_decoded = buffer->nFilledLen;
+
+  if (!CanAcceptOutput()) {
+    if (uses_egl_image_) {
+      scoped_refptr<VideoFrame> frame;
+      frame = static_cast<VideoFrame*>(buffer->pAppPrivate);
+      event_handler_->ConsumeVideoFrame(frame, statistics);
+      output_pending_request_--;
+    }
+    return;
+  }
+
+  // This buffer is received with decoded frame. Enqueue it and make it
+  // ready to be consumed by reads.
+
+  if (buffer->nFlags & OMX_BUFFERFLAG_EOS) {
+    output_eos_ = true;
+    DLOG(INFO) << "Output has EOS";
+  }
+
+  FinishFillBuffer(buffer);
+
+  if (buffer->nFlags & OMX_BUFFERFLAG_EOS) {
+    // Singal end of stream.
+    scoped_refptr<VideoFrame> frame;
+    VideoFrame::CreateEmptyFrame(&frame);
+    event_handler_->ConsumeVideoFrame(frame, statistics);
+  }
+
+  if (client_state_ == kClientFlushing &&
+      InputPortFlushed() && OutputPortFlushed())
+    ComponentFlushDone();
+}
+
+void OmxVideoDecodeEngine::EventHandlerCompleteTask(OMX_EVENTTYPE event,
+                                                    OMX_U32 data1,
+                                                    OMX_U32 data2) {
+  switch (event) {
+    case OMX_EventCmdComplete: {
+      // If the last command was successful, we have completed
+      // a state transition. So notify that we have done it
+      // accordingly.
+      OMX_COMMANDTYPE cmd = static_cast<OMX_COMMANDTYPE>(data1);
+      if (cmd == OMX_CommandPortDisable) {
+        if (OnPortDisableEventFunc)
+          (this->*OnPortDisableEventFunc)(static_cast<int>(data2));
+      } else if (cmd == OMX_CommandPortEnable) {
+        if (OnPortEnableEventFunc)
+          (this->*OnPortEnableEventFunc)(static_cast<int>(data2));
+      } else if (cmd == OMX_CommandStateSet) {
+        (this->*OnStateSetEventFunc)(static_cast<OMX_STATETYPE>(data2));
+      } else if (cmd == OMX_CommandFlush) {
+        (this->*OnFlushEventFunc)(data2);
+      } else {
+        LOG(ERROR) << "Unknown command completed\n" << data1;
+      }
+      break;
+    }
+    case OMX_EventError:
+      if (OMX_ErrorInvalidState == (OMX_ERRORTYPE)data1) {
+        // TODO(hclam): what to do here?
+      }
+      StopOnError();
+      break;
+    case OMX_EventPortSettingsChanged:
+      // TODO(wjia): remove this hack when all vendors observe same spec.
+      if (data1 < OMX_IndexComponentStartUnused)
+        OnPortSettingsChangedRun(static_cast<int>(data1),
+                                 static_cast<OMX_INDEXTYPE>(data2));
+      else
+        OnPortSettingsChangedRun(static_cast<int>(data2),
+                                 static_cast<OMX_INDEXTYPE>(data1));
+      break;
+    default:
+      LOG(ERROR) << "Warning - Unknown event received\n";
+      break;
+  }
+}
+
+// static
+OMX_ERRORTYPE OmxVideoDecodeEngine::EventHandler(OMX_HANDLETYPE component,
+                                     OMX_PTR priv_data,
+                                     OMX_EVENTTYPE event,
+                                     OMX_U32 data1,
+                                     OMX_U32 data2,
+                                     OMX_PTR event_data) {
+  OmxVideoDecodeEngine* decoder = static_cast<OmxVideoDecodeEngine*>(priv_data);
+  DCHECK_EQ(component, decoder->component_handle_);
+  decoder->message_loop_->PostTask(FROM_HERE,
+      NewRunnableMethod(decoder,
+                        &OmxVideoDecodeEngine::EventHandlerCompleteTask,
+                        event, data1, data2));
+  return OMX_ErrorNone;
+}
+
+// static
+OMX_ERRORTYPE OmxVideoDecodeEngine::EmptyBufferCallback(
+    OMX_HANDLETYPE component,
+    OMX_PTR priv_data,
+    OMX_BUFFERHEADERTYPE* buffer) {
+  OmxVideoDecodeEngine* decoder = static_cast<OmxVideoDecodeEngine*>(priv_data);
+  DCHECK_EQ(component, decoder->component_handle_);
+  decoder->message_loop_->PostTask(FROM_HERE,
+      NewRunnableMethod(decoder,
+                        &OmxVideoDecodeEngine::EmptyBufferDoneTask, buffer));
+  return OMX_ErrorNone;
+}
+
+// static
+OMX_ERRORTYPE OmxVideoDecodeEngine::FillBufferCallback(
+    OMX_HANDLETYPE component,
+    OMX_PTR priv_data,
+    OMX_BUFFERHEADERTYPE* buffer) {
+  OmxVideoDecodeEngine* decoder = static_cast<OmxVideoDecodeEngine*>(priv_data);
+  DCHECK_EQ(component, decoder->component_handle_);
+  decoder->message_loop_->PostTask(FROM_HERE,
+      NewRunnableMethod(decoder,
+                        &OmxVideoDecodeEngine::FillBufferDoneTask, buffer));
+  return OMX_ErrorNone;
+}
+
+}  // namespace media
+
+// Disable refcounting for this object because this object only lives
+// on the video decoder thread and there's no need to refcount it.
+DISABLE_RUNNABLE_METHOD_REFCOUNT(media::OmxVideoDecodeEngine);
diff --git a/media/video/omx_video_decode_engine.h b/media/video/omx_video_decode_engine.h
new file mode 100644
index 0000000..e9cc756
--- /dev/null
+++ b/media/video/omx_video_decode_engine.h
@@ -0,0 +1,246 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MEDIA_VIDEO_OMX_VIDEO_DECODE_ENGINE_H_
+#define MEDIA_VIDEO_OMX_VIDEO_DECODE_ENGINE_H_
+
+#include <queue>
+#include <utility>
+#include <vector>
+
+#include "base/callback_old.h"
+#include "base/memory/scoped_ptr.h"
+#include "media/omx/omx_configurator.h"
+#include "media/video/video_decode_engine.h"
+#include "third_party/openmax/il/OMX_Component.h"
+#include "third_party/openmax/il/OMX_Core.h"
+#include "third_party/openmax/il/OMX_Video.h"
+
+namespace media {
+
+class OmxVideoDecodeEngine : public VideoDecodeEngine {
+ public:
+  OmxVideoDecodeEngine();
+  virtual ~OmxVideoDecodeEngine();
+
+  // Implementation of the VideoDecodeEngine Interface.
+  virtual void Initialize(MessageLoop* message_loop,
+                          VideoDecodeEngine::EventHandler* event_handler,
+                          VideoDecodeContext* context,
+                          const VideoDecoderConfig& config);
+  virtual void ConsumeVideoSample(scoped_refptr<Buffer> buffer);
+  virtual void ProduceVideoFrame(scoped_refptr<VideoFrame> frame);
+  virtual void Uninitialize();
+  virtual void Flush();
+  virtual void Seek();
+
+  // Subclass can provide a different value.
+  virtual int current_omx_spec_version() const;
+
+ private:
+  enum OmxIlState {
+    kIlNone,
+    kIlLoaded,
+    kIlIdle,
+    kIlExecuting,
+    kIlPause,
+    kIlInvalid,
+    kIlUnknown,
+  };
+
+  enum OmxIlClientState {
+    kClientNotInitialized,
+    kClientInitializing,
+    kClientRunning,
+    kClientStopping,
+    kClientStopped,
+    kClientPausing,
+    kClientFlushing,
+    kClientError,
+  };
+
+  enum OmxIlPortState {
+    kPortDisabled,
+    kPortEnabling,
+    kPortEnabled,
+    kPortDisabling,
+  };
+
+  typedef Callback0::Type Callback;
+
+  // calls into other classes
+  void FinishEmptyBuffer(scoped_refptr<Buffer> buffer);
+  void FinishFillBuffer(OMX_BUFFERHEADERTYPE* buffer);
+  // Helper method to perform tasks when this object is stopped.
+  void OnStopDone();
+
+  // Transition method sequence for initialization
+  bool CreateComponent();
+  void DoneSetStateIdle(OMX_STATETYPE state);
+  void DoneSetStateExecuting(OMX_STATETYPE state);
+  void OnPortSettingsChangedRun(int port, OMX_INDEXTYPE index);
+  void OnPortDisableEventRun(int port);
+  void SetupOutputPort();
+  void OnPortEnableEventRun(int port);
+
+  // Transition methods for shutdown
+  void DeinitFromExecuting(OMX_STATETYPE state);
+  void DeinitFromIdle(OMX_STATETYPE state);
+  void DeinitFromLoaded(OMX_STATETYPE state);
+  void PauseFromExecuting(OMX_STATETYPE state);
+  void StartFlush();
+  void PortFlushDone(int port);
+  void ComponentFlushDone();
+
+  void StopOnError();
+
+  void InitializeTask();
+
+  // Methods to free input and output buffers.
+  bool AllocateInputBuffers();
+  bool AllocateOutputBuffers();
+  void FreeInputBuffers();
+  void FreeOutputBuffers();
+  void FreeInputQueue();
+
+  // Helper method to configure port format at LOADED state.
+  bool ConfigureIOPorts();
+
+  // Determine whether we can issue fill buffer or empty buffer
+  // to the decoder based on the current state and port state.
+  bool CanEmptyBuffer();
+  bool CanFillBuffer();
+
+  // Determine whether we can use |input_queue_| and |output_queue_|
+  // based on the current state.
+  bool CanAcceptInput();
+  bool CanAcceptOutput();
+
+  bool InputPortFlushed();
+  bool OutputPortFlushed();
+
+  // Method to send input buffers to component
+  void EmptyBufferTask();
+
+  // Method doing initial reads to get bit stream from demuxer.
+  void InitialReadBuffer();
+
+  // Method doing initial fills to kick start the decoding process.
+  void InitialFillBuffer();
+
+  // helper functions
+  void ChangePort(OMX_COMMANDTYPE cmd, int port_index);
+  OMX_BUFFERHEADERTYPE* FindOmxBuffer(scoped_refptr<VideoFrame> video_frame);
+  OMX_STATETYPE GetComponentState();
+  void SendOutputBufferToComponent(OMX_BUFFERHEADERTYPE *omx_buffer);
+  bool TransitionToState(OMX_STATETYPE new_state);
+  virtual VideoFrame::Format GetSurfaceFormat() const;
+
+  // Method to handle events
+  void EventHandlerCompleteTask(OMX_EVENTTYPE event,
+                                OMX_U32 data1,
+                                OMX_U32 data2);
+
+  // Method to receive buffers from component's input port
+  void EmptyBufferDoneTask(OMX_BUFFERHEADERTYPE* buffer);
+
+  // Method to receive buffers from component's output port
+  void FillBufferDoneTask(OMX_BUFFERHEADERTYPE* buffer);
+
+  // The following three methods are static callback methods
+  // for the OMX component. When these callbacks are received, the
+  // call is delegated to the three internal methods above.
+  static OMX_ERRORTYPE EventHandler(OMX_HANDLETYPE component,
+                                    OMX_PTR priv_data,
+                                    OMX_EVENTTYPE event,
+                                    OMX_U32 data1, OMX_U32 data2,
+                                    OMX_PTR event_data);
+
+  static OMX_ERRORTYPE EmptyBufferCallback(OMX_HANDLETYPE component,
+                                           OMX_PTR priv_data,
+                                           OMX_BUFFERHEADERTYPE* buffer);
+
+  static OMX_ERRORTYPE FillBufferCallback(OMX_HANDLETYPE component,
+                                          OMX_PTR priv_data,
+                                          OMX_BUFFERHEADERTYPE* buffer);
+
+  // Member function pointers to respond to events
+  void (OmxVideoDecodeEngine::*OnPortDisableEventFunc)(int port);
+  void (OmxVideoDecodeEngine::*OnPortEnableEventFunc)(int port);
+  void (OmxVideoDecodeEngine::*OnStateSetEventFunc)(OMX_STATETYPE state);
+  void (OmxVideoDecodeEngine::*OnFlushEventFunc)(int port);
+
+  // Helper function
+  scoped_refptr<VideoFrame> CreateOmxBufferVideoFrame(
+      OMX_BUFFERHEADERTYPE* omx_buffer);
+
+  int width_;
+  int height_;
+
+  MessageLoop* message_loop_;
+
+  std::vector<OMX_BUFFERHEADERTYPE*> input_buffers_;
+  int input_buffer_count_;
+  int input_buffer_size_;
+  int input_port_;
+  int input_buffers_at_component_;
+  int input_pending_request_;
+  bool input_queue_has_eos_;
+  bool input_has_fed_eos_;
+  bool input_port_flushed_;
+
+  int output_buffer_count_;
+  int output_buffer_size_;
+  int output_port_;
+  int output_buffers_at_component_;
+  int output_pending_request_;
+  bool output_eos_;
+  bool output_port_flushed_;
+  bool uses_egl_image_;
+  base::TimeDelta last_pts_;
+
+  // |il_state_| records the current component state. During state transition
+  // |expected_il_state_| is the next state that the component will transition
+  // to. After a state transition is completed, |il_state_| equals
+  // |expected_il_state_|. Inequality can be used to detect a state transition.
+  // These two members are read and written only on |message_loop_|.
+  OmxIlState il_state_;
+  OmxIlState expected_il_state_;
+  OmxIlClientState client_state_;
+
+  OMX_HANDLETYPE component_handle_;
+  scoped_ptr<media::OmxConfigurator> configurator_;
+
+  // Free input OpenMAX buffers that can be used to take input bitstream from
+  // demuxer.
+  std::queue<OMX_BUFFERHEADERTYPE*> free_input_buffers_;
+
+  // Available input OpenMAX buffers that we can use to issue
+  // OMX_EmptyThisBuffer() call.
+  std::queue<OMX_BUFFERHEADERTYPE*> available_input_buffers_;
+
+  // flag for freeing input/output buffers
+  bool need_free_input_buffers_;
+  bool need_free_output_buffers_;
+
+  // for calling flush callback only once.
+  bool flush_pending_;
+
+  // For output buffer recycling cases.
+  typedef std::pair<scoped_refptr<VideoFrame>,
+                    OMX_BUFFERHEADERTYPE*> OutputFrame;
+  std::vector<OutputFrame> output_frames_;
+  bool output_frames_allocated_;
+
+  // port related
+  bool need_setup_output_port_;
+  OmxIlPortState output_port_state_;
+  VideoDecodeEngine::EventHandler* event_handler_;
+
+  DISALLOW_COPY_AND_ASSIGN(OmxVideoDecodeEngine);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_VIDEO_OMX_VIDEO_DECODE_ENGINE_H_